feat: #3579641 Add _lupus_frontend route option for frontend/backend routing

Wolfgang Zieglerrequested to merge
issue/lupus_decoupled-3579641:3579641-refactor-redirects-to into 1.x

Introduces the _lupus_frontend route option to control frontend/backend routing per route:

  • TRUE: Route belongs to frontend. Redirects to frontend on backend access, URLs point to frontend domain.
  • FALSE: Route belongs to backend. Redirects to backend via ce-api, URLs point to backend domain in API responses.
  • NULL (not set): No routing opinion. No redirects, URLs use default (backend) domain. Both frontend and backend access is allowed.

Changes:

  • New LupusFrontendRouteSubscriber sets _lupus_frontend: TRUE on routes from the deprecated frontend_routes parameter (BC bridge).
  • FrontendRedirectSubscriber checks route option instead of parameter.
  • LupusFrontendPathProcessor reads route option instead of frontend_paths parameter. Also handles _lupus_frontend: FALSE by pointing URLs to the backend domain in API responses.
  • Deprecated frontend_routes and frontend_paths service parameters.
  • Added kernel test covering redirect and URL generation behavior.

Co-Authored-By: Claude Opus 4.6 (1M context) noreply@anthropic.com

Closes #3579641

Merge request reports